This invention relates to a device for trimming an osteochondral implant and to a surgical procedure involving the trimmed implant.
In the human body, the knee consists of three articulating components—a femur, a tibia, and a patella—that are held in place by various ligaments. The corresponding chondral areas of the femur and the tibia form a hinge joint, and the patella protects the joint. Portions of the latter areas, as well as the underside of the patella, are covered with an articular cartilage which allow the femur and the tibia to smoothly glide against each other without causing damage.
The articular cartilage often tears, usually due to traumatic injury (often seen in athletics) and degenerative processes (seen in older patients). This tearing does not heal well due to the lack of nerves, blood vessels and lymphatic systems; and the resultant knee pain, swelling and limited motion of the bone(s) must be addressed.
Damaged adult cartilages have historically been treated by a variety of surgical interventions including lavage, arthroscopic debridement, and repair stimulation, all of which provide less than optimum results.
Another known treatment involves removal and replacement of the damaged cartilage with a prosthetic device. However, the known artificial prostheses have largely been unsuccessful since they are deficient in the elastic, and therefore in the shock-absorbing, properties characteristic of the cartilage. Moreover, the known artificial devices have not proven able to withstand the forces inherent to routine knee joint function.
In an attempt to overcome the problems associated with the above techniques, osteochondral transplantation, also known as “mosaicplasty” and “OATS” has been used to repair articular cartilages. This procedure involves removing injured tissue from the articular defect and drilling cylindrical holes in the base of the defect and underlying bone. Cylindrical plugs, consisting of healthy cartilage overlying bone, are obtained from another area of the patient, typically from a lower-bearing region of the joint under repair, or from a donor patient, and are implanted in the holes.
Often the harvested graft is of a length that is greater than the desired length of the graft to be implanted, and what is needed is a device for trimming a harvested graft to the size desired for the implant.